Strike securing device



May 24, 1966 E- L. scHLAGE 3,252,494

STRIKE SECURING DEVICE Original Filed May 10, 1963 2 Sheets-Sheet l May24, 1966 E. 1... sea-amass STRIKE SECURING DEVICE 2 Sheets-Sheet 2Original Filed May 10 1963 INVENTOR. ERNEST L. SCHLAGE A TTO/PNE) UnitedStates Patent 3,252,494 STRIKE SECURING DEVICE Ernest L. Schlage,Bnrlingame, Calif., assignor to Schlage Lock Company, a corporationOriginal application May 10, 1963, Ser. No. 279,565; Divided and thisapplication Apr. 3, 1964, Ser. No. 357,193

1 Claim. (Cl. 151-4113) This application is a division of Serial No.279,565 filed May 10, 1963.

3,252,494 Patented May 24, 1966 FIG. 6 is a horizontal cross sectionthrough the bore This invention relates to a strike for a door lock andmore particularly to a combination strike plate and strike box which isadapted to be mounted in a bore in a door jamb. The invention alsoprovides novel fastening means for fastening a strike or similar articlewithin a cylindrical opening.

Heretofore it has been customary to make strikes generally rectangularin shape and to sink them in a mortise in a door jamb and secure thestrike plate by means of screws. It is desirable to economize on thelabor involved in the installation of the strike and in the cost ofmanufacture. Also, it is desirable to include a strike box integral withthe strike plate so that only one element is required to be secured tothe door jamb.

An attempt has heretofore been made to apply a combination strike plateand strike box to a jamb by providing bores into which the box isreceived. Although this technique is desirable in that it obviates thetime consuming step of forming a cavity for the strike box by means ofchiseling, no successful method has been evolved for securing acombination strike plate and strikev box in a single bored hole.

The main object of the present invention is to provide a novel strikeplate and strike box combination which has advantages both in economy ofmanufacture and ease of installation.

Another object of the invention is the provision of an improvedfastening means to permit a secure installation of the strike plate andbox combination with a door jamb which requires only the use of a boringtool and a screw driver.

Still another object of the invention is the provision of a surfacemounted strike which requires no mortising and which may be removed fromthe door jamb for the purpose of replacement without mutilating saidjamb.

Yet another object of the invention is the provision of an improvedfastening element that may be used as an anchor within a cylindricalopening for securing a member at the outer end of said opening.

Another object of the invention is the provision of a combination strikeplate and strike box together with fastening means therefor which neednot be separated from the strike plate and strike box during the stepsof instal lation.

Another object of the invention is the provision of a captive screwwhich may be incorporated in a fastening assembly without inadvertentlybecoming detached from said assembly.

Other objects and advantages of the present invention will be seen fromthe following specification and drawings wherein:

and securing means assembled.

FIG. 7 is an enlarged cross section through the bottom of the strike boxshowing the screw in relation to said bottom in its normal positionafter the thread of the screw has mutilated the plate so as to preventaxial movement of the screw relative to the plate.

FIG. 8 is a rear elevation of a modified form of gripping elementshowing the surrounding structure in dot-dash lines.

FIG. 9 in a side elevation of the gripping element of FIG. 8.

In detail, and first with reference to FIG. 2, the invention is adaptedto be employed on a door jamb 1 provided with a door stop 2. It will beunderstood that the door (not shown) swings from a door jamb oppositejamb land one face of the door fits, in its closed position, against theface 3 of the stop 2 with the opposite face of the door usuallysubstantially coplanar with the face 4 of the jamb 1.

By the present invention a strike plate 10 is applied to the face 11 ofthe jamb and said strike plate has integrally connected thereto a strikebox 9 having upper and lower walls 12, 13, an outer wall 14substantially perpendicular to face 11 of jamb 1, and an innerslantingly disposed wall 15. It will be apparent that the outline of theline of 'intersection of the strike plate with the walls of the strikebox is generally D-shaped so as to correspond with the conventionalcross sectional contour of the latchbolt (not shown) of the lockset.Said latch-bolt, when projected into the strike box as the door isclosed, is provided with a flat face which lies alongside the sidewall14 of the strike box (FIG. 6).

The strike plate 10 is shown as surface mounted in FIG. 2; that is, thestrike plate is secured against the face 11 of the jamb 1. However, ifdesired, a mortise may be formed in the face of the jamb so as to sinkthe strike plate into the jamb and make the outer surface of the strikeplate coplanar with the face 11 of the jamb. In such a case, a generallytrapezoidal shaped mortise is formed so as to register with theconverging upper and lower edges 20, 21 of the strike plate and theinner vertical edge 22. The outer portion of the strike plate terminatesin the usual curved cam portion 23 which serves to depress the latchboltas the door moves toward closed position.

At this point it will be noted that when the strike plate is used with amortised jamb the novel trapezoidal shape shown enhances the resistanceof the strike plate to being shifted relative to the jam-b when the dooris slammed. This is because the material of the jamb adjacent edges 20,21 offers additional resistance to such failure as compared, forexample, to parallel edges which would contribute no additionalresistance. It should be understood in this connection that the forcetending to cause failure is the force of rebound of the door from thestop 2 and not the closing force of the door itself. When thestrikeplate is surface mounted the strengthening effect of the trapezoidalshape is also present, although to a lesser degree, because the strikeplate is very tightly abutted against the face 11 of the jamb therebyslightly compressing said face.

An advantage over circular strikes is also present in the trapezoidalshape of the instant strike plate in that the vertically disposed edge22 may be made very close to the latch opening thereby giving greaterclearance between said edge 22 and the adjacent door stop 2. With acircular strike plate in which the outer periphery of the plate is madeconcentric with the bore in the jamb, interference frequently existsbetween the edge of the plate and the door stop, particularly in thecase of thin doors and narrow jambs.

:3 By the present invention substantial savings in the cost of mountingthe strike plate structure are effected, first, by surface mounting thestrike plate, and, second, by securing the strike plate and strike boxcombination in a cylindrical hole in the jamb which may be bored in amatter of seconds.

If it is desired to sink the trapezoidal shaped strike plate in amortise it will be noted that only three straight cuts need be made todo so. This feature is particularly important if it is found desirableto form such a mortise after the cavity for the strike box has beenformed. In the case of a circular strike it is virtually impossible toform a circular mortise without a boring tool of some kind and thestrike box cavity eliminates the center for the use of such a tool.

As best seen in FIG. 6 a bore 30 is formed in jamb 1 opening outwardlyof face 11 and in coaxial alignment with the latchbolt (not shown) whenthe door is closed. Bore 30 is of a size to accommodate the strike box9, and upper and lower walls 12, 13 of said strike box may be curved soas to be snugly received adjacent the inner sidewalls of said bore.

Strike box 9 is provided with a bottom wall 31 in which a circular hole32 is formed to receive therethrough a screw 33. Hole 32 is positionedin bottom 31 so as to be coaxial with the centerline of bore 30 and, ofcourse, the line of action of the latchbolt. Only one screw 33 is reliedon to secure the strike plate structure in place because it isdesirable, at installation, to be able to swing the combined strikeplate and box about the axis of screw 33 so as to adjustably set thesame in a position with the fiat side 14 of box 9 parallel to the fiatface of the latchbolt in the event the latchbolt is installed with itsfiat face in a tilted position relative to its proper vertical setting.Such permitted rotation is also useful in taking up play between thelatchbolt and strike, thereby eliminating door rattle.

If the strike plate is installed before the door jamb is secured inplace, it is, of course, a simple matter to provide an anchor plate orsome other device on the opposite side of jamb 1 from face 11 so as toreceive a machine screw or the like fastening element therethrough totighten the strike plate and box in the position of FIG. 6. The presentinvention, however, provides means for fixedly securing the strike plateand box in place after, as well as before, the jamb is installed andwhen access to the inner side of the jamb is prevented.

The means for receiving the inner end of screw 33 is a gripping plate oranchor generally designated 36 (FIGS. 3-6). As best seen in FIG. 4 theanchor or gripping plate 36 is preferably formed from a section of sheetmaterial in the order of .015 inch thick and comprises a central portion37 (FIG. 4) which is apertured as at 38 to receive screw 33therethrough. In order to facilitate reception of the screw 33 asubstantially semicircular portion 40 is partially struck out from theplate to form a partial helix complementary to the helix of the screw.

As best seen in FIG. 5, the gripping plate is dished to a generallyspherical shape so as to enhance the resistance of the plate todiaphragming, and the helix receiving portion 40 is formed on the convexside. It willbe seen that the dished shape of the grippling platefacilitates insertion of the same in the bore 30.

Extending outwardly from the central portion 37 of the plate 36 are aplurality of legs 42. Three legs are shown in FIG. 4 so as to form' atriskelion shape, but it will be apparent that a greater number of legsmay be formed. Although the device may operate in the desired mannerwith two such legs, it is preferable that three or more legs be employedto obtain an even distribution of loading. a

In forming the gripping element 36 each leg 42 is defined by cutting theplate to provide an edge 43 on each leg and an adjacent edge 44 on thecentral portion of the plate. At the end of each such cut the plate is 4provided with a small circular aperture 45 which not only reduces thestress concentration but also facilitates deflecting the legs with apermanent set toward the center of the plate as shown in FIG. 4 toprovide an overlapping portion 46.

The gripper plate is heat treated after being formed as above describedso that a strong resilient anchor is provided.

The parts of FIG. 3 are assembled by threading screw 33 through hole 32in the bottom 31 of the strike box until the head of the screw isagainst said bottom. The gripper element 36 is then threaded onto theend of the screw for a few threads to about the position shown in FIG.6. At installation the entire assembly may be pressed into bore 39 withthe convex side of gripper element 36 leading until the inner side ofstrike plate 10 abuts face 11 of jamb 1. During this step the legs 42 ofthe gripper element deflect toward the open end of the bore 30 so thatthe sharp outer ends 47 of said legs prevent the reverse movement of thegripper plate.

The strike plate 10 may then be tightened against the face 11 of jamb 1simply by rotating screw 33 with a screw driver. It will be noted thatany tendency that the gripper plate 36 may have to rotate with the screwis eliminate-d by the fact that the sharp ends 47 of the legs 42 diginto the sidewalls of the bore. The direction in which the legs 42 aredisposed is, of course, made the same as the direction of rotation ofthe screw 33 when the latter is tightened.

Before the screw 33 is tightened, it is apparent that the step ofpressing the gripper element 36 into the bore 30 will have resulted inthe central body portion 37 of the gripper element being spaced slightlyinwardly from the adjacent legs. Thus, as screw 33 is tightened thecentral portion 37 of the gripper element is pulled outwardly toward theopen end of the bore 30 against the inherent resistance of the materialof the plate. However, substantially increased resistance to outwardmovement of the plate is encountered when the central portion abuts thelegs 42 along the overlapping portions 46. By this structure, failure ofthe gripper plate or screw cannot take place without the application ofan inordinate amount of torque on screw 33. The result is that strikeplate 10 may be pulled against face 11 of jamb 1 with an extremely highpressure so that there is no tendency for the strike plate to shift evenunder rough usage.

An important feature of the invention resides in the fact that thestrike plate may readily be removed and another substituted if thisbecomes desirable. For such replacement it is merely necessary tounscrew screw 33, and remove the strike and gripper plate 36 ifnecessary. The procedure hereinabove described may then be followed forinstallation of the new strike plate and box.

Another important feature of the invention resides in the fact that thestrike, the gripper element and the screw may be packaged in anassembled condition as shown in FIG. 6 so that it is merely necessaryfor the carpenter to remove the assembly from its package and apply itto the bore. To obviate the possibility of the screw 33 becoming looseit is assembled with the bottom of the strike box as shown in FIG. 7. Asan example, the screw 33 may be long, 18 threads per inch, with themajor diameter of the threads about .138" and a thread pitch of .056".

By employing a plate about .035" thick to form the bottom 31 anddrilling hole 32 to a diameter of .110" the screw 33 bay be threadedinto hole 32 until the head of the screw abuts the bottom. By continuingto turn screw 33 after the head of the screw engages the outer side ofthe bottom 31, the inner side of the bottom is mutilated by the adjacentend of the thread to the shape shown in FIG. 7. Such mutilation takesplace because the screw is hardened steel and the strike plate and boxis made of much softer material, preferably brass.

The additional turns of the screw after the same has been completelythreaded through hole 32 causes the sharp end of the screw to cut a chipfrom the adjacent circular edge of the hole and, at the same time, toupset the adjacent material until a frustoconical portion 48 is formed.This formation prevents the thread of the screw from biting into thematerial of the bottom 31 when the direction of rotation of the screw isreversed if it is attempted to unscrew the screw from the bottom. Bythis construction there is no likelihood of the screw becoming detachedfrom the strike or being pushed outwardly of the hole 32 by the reactionof the gripper during installation.

At assembly, and prior to packaging, it is merely necessary to threadthe gripper element 36 onto the end of screw 33 for a few turns of thelatter before packaging the same. I

A modified form of gripper element generally designated 50 is shown inFIGS. 8, 9. Use of a gripper element of this type is advisable in someinstances if the thickness of the wood between the bore 30 and the outerface 4 of the jamb is so small that one of the legs 42 of gripperelement might penetrate the thin wall 60.

The device of FIGS. 8, 9 is designed to ensure that a sharp point of thegripper will never register with the thinnest section of the wood 60between bore 30 and the outer face 4 of the jamb.

The gripper element 50 comprises a central section 51 from which extendsa pair of relatively narrow legs 52, 53 which are angularly oifset at anangle of about 100. Another pair of generally parallel legs 54, 55extend generally horizontal from the central portion 51.

A positioning flange 57, centrally between legs 52, 53 is bent at rightangles to the central portion 51 so that it engages the flat sidewall 14of the strike box 9 when the gripper element is secured to the screw 33(not shown in FIG. 9). In all other respects the element 50 is similarto the above described element 36, having a central aperture 58 forreceiving the screw 33 therethrough, and an upset partially annularportion 59 surrounding said aperture.

It will be apparent from FIGS. 8, 9 that when gripper element 50 issecured by screw 33 to the combination strike and strike box, the flange57, although permitting relative axial movement between the gripperelement and the strike box, limits relative rotation. Thus the legs 52,53 remain at all times in a position angularly offset from 6 the narrowsection 60 of the door jamb and there is no chance of any one of thelegs registering with said narrow section.

The above very specific description of preferred forms of the inventionshould not be taken as restrictive of the invention as it will beapparent that various modifications in design may be resorted to withoutdeparting from the following claim.

I claim: A fastening device adapted to be received transversely withinan opening having an open end and radially inwardly directed sidewalls,comprising:

a central body portion having a central aperture for receiving a screwtherethrough from said open end,

said body portion being formed of thin resilient sheet metal and bowedto provide a concave side facing outwardly of said opening,

a plurality of legs integral with said body and in outward extensionthereof and adapted to engage said sidewalls at their outer ends,

said legs extending radially outwardly and tangentially relative to saidopening and being bent generally in the plane of said body with portionsof said legs in lapping relation to portions of said body portion atsaid concave side thereof,

said legs being pointed at their outer ends and adapted to be embeddedin the sidewalls of said bore when said screw is tightened.

References Cited by the Examiner UNITED STATES PATENTS 1,960,381 5/1934Knapp 15l--4l.74 2,640,219 6/1953 Becker 36 2,654,620 10/ 1953 Timmerman1514l.73 2,982,989 5/1961 Heyer 15141.73 3,079,493 2/ 1963 Goldstein151--41.73

FOREIGN PATENTS 647,302 12/1950 Great Britain. 327,410 7/ 1958Switzerland.

CARL W. TOMLIN, Primary Examiner. MARION PARSONS, JR., AssistantExaminer.

